sendmail: use FQDN in default envelope sender

RFC 5321 requires the return path to be supplied with a proper domain
name.

Signed-off-by: Kaarle Ritvanen <kaarle.ritvanen@datakunkku.fi>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
libbb: don't die if crypt() returns NULL

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
htpd: trivial simplification in random interval selection

function                                             old     new   delta
poll_interval                                         57      52      -5

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>